1. Field of the Invention
The present invention relates to an illumination device and a projection display device using the same, and more particularly, is suitable for use in a case where a plurality of laser light sources are linearly arranged.
2. Disclosure of Related Art
Conventionally, in a projection display device (hereinafter, referred to as a “projector”), a lamp light source such as an ultra-high pressure mercury lamp, a metal halide lamp, or a xenon lamp has been used as an emission light source. Meanwhile, in recent years, a projector using a laser light source has been under development. A laser light source has a high level of capability to express a wide color space with high brightness and high definition, and is receiving attention as a light source for next-generation projectors.
In such a display device, the brightness of illumination light can be raised by arranging and arraying a plurality of laser light source in two dimensions. In arranging a plurality of laser light sources in such a manner, a means for reducing non-uniformity in illumination light may be utilized. For example, the means detects any laser light source having an output shortage or in an unlit state, and controls the laser light sources based on the detection results.
In general, a plurality of laser light sources are linearly aligned in such a manner as to be close to each other. In this case, an illuminance distribution of illumination light emitted from the linearly aligned laser light sources, is prone to be uniform in a direction of arrangement. Accordingly, if fly-eye lenses are arranged such that the laser light sources and fly-eye lens cells are aligned in parallel to each other, the effectiveness of illumination light superimposition by the fly-eye lenses is deteriorated, thereby causing non-uniformity in an illumination distribution of illumination light on an imager.